Field of the Invention
The present invention relates to an indexable cutting insert for face milling with high feed rates, and to a milling tool for face milling with high feed rates, with a plurality of such indexable cutting inserts.
When machining in particular metallic materials by milling, it is customary to use milling tools which have a relatively tough carrier body which can be manufactured, for example, from tool steel to which a plurality of cutting inserts made of a harder, more wear-resistant material, in particular cemented-carbide, cermet or cutting ceramic, is fastened. The cutting inserts here have the cutting edges which enter into engagement in a machining manner with the workpiece to be machined. It is known in particular to design the cutting inserts as what as referred to as indexable cutting inserts which have a plurality of identical cutting edges useable in succession. The individual cutting edges are customarily indexed here by rotation of the respective cutting insert about one or more axes of symmetry (for example by 90°, 120°, 180°, 240°, 270° or other angles).
Different geometries are used here for the milling tools and the cutting inserts depending on the intended use. One use region is face milling with high feed rates, in which the milling operation is carried out at relatively low depths of cut, but at relatively high feed rates in the direction parallel to the workpiece surface to be machined.
In milling operations of this type, because of the high feed rate, relatively long cutting edge portions come into engagement with the workpiece to be machined, and it is important to provide as balanced as possible a distribution of the cutting forces at the cutting edge in order to achieve a long service life of the cutting insert.
JP S52-103081 A presents a miller with a carrier body which is equipped with a plurality of exchangeable cutting inserts which each have cutting edge portions which are convexly arched at least in sections.
Indexable cutting inserts composed of cemented carbide or cermet are customarily produced in a powder-metallurgical production process from starting powders which are mixed in accordance with the desired composition, are pressed in a mold into the desired shape and are subsequently sintered to form solid bodies. During the sintering of the pressed green compacts, compaction of the material occurs, which compaction is associated with shrinkage, wherein the uniformity of said shrinkage is greatly influenced by the geometry of the green compact and the pressure distribution achieved during the pressing. It has been shown that the service life which can be achieved for cutting inserts produced by powder-metallurgy greatly depends on the successful control of the powder-metallurgical production process.